Planning Department Agreement No. PLNQ 56/2012 Category B
Total Page：16
File Type：pdf, Size：1020Kb
Planning Department Agreement No. PLNQ 56/2012 Category B - Term Consultancy for Air Ventilation Assessment by Computational Fluid Dynamics Container Terminals No.1 to 9 Air Ventilation Assessment Executive Summary April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary Table of Contents Page 1 INTRODUCTION ........................................................................................................... 4 2 WIND AVAILABILITY .................................................................................................... 4 3 EXISTING SITE CONDITIONS ..................................................................................... 5 4 ASSESSMENT METHODOLOGY AND TESTPOINTS LOCATIONS .......................... 7 5 DEVELOPMENT SCENARIOS ..................................................................................... 8 6 KEY FINDINGS OF AVA STUDY ............................................................................... 14 7 REVISED SCENARIO C AND RELATED ASSESSMENT ......................................... 24 8 SUMMARY AND CONCLUSION ................................................................................ 30 List of Figures Figure 2.1 Annual and Summer Prevailing Wind Rose at 450m Elevation Figure 3.1 Project Area, Assessment Area, Surrounding Area and Prevailing wind directions Figure 5.1 Layout Plan for Baseline Scenario Figure 5.2 Layout Plan for Scenario A Figure 5.3 Layout Plan for Scenario B Figure 5.4 Layout Plan for Scenario C Figure 5.5 Planning Features incorporated in Revised Scenario C Figure 6.1 Annual Frequency Weighted Wind Velocity Ratio Contour Plot at 2m above Ground Level Figure 6.2 Summer Frequency Weighted Wind Velocity Ratio Contour Plot at 2m above Figure 6.3 Wind Velocity Ratio Contour Plot at 2m above Ground Level (E wind) Figure 6.4 Wind Velocity Ratio Contour Plot at 2m above Ground Level (SE wind) Figure 6.5 Wind Velocity Ratio Contour Plot at 2m above Ground Level (S wind) Figure 6.6 Wind Velocity Ratio Contour Plot at 2m above Ground Level (SSW wind) Figure 7.1 Size of Wake Regions due to Difference in Building Height under S wind Figure 7.2 Contour Plots at 2m above ground under summer SW prevailing wind Figure 7.3 Illustrational Diagram of NBA between CT5 West and CT1 Figure 7.4 Pathlines above T4 Crosswharf under summer SW wind in Scenario C Figure 7.5 Contour Plots at 2m above ground under SW, SSW and WSW prevailing winds Figure 7.6 Layout Plan for Further Revised Scenario C at T4 Crosswharf Figure 7.7 Contour Plots at 2m above ground under ESE prevailing wind AECOM Asia Co. Ltd. 2 April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary List of Tables Table 6.1 Summary of Wind Velocity Ratios under Annual Wind Directions Table 6.2 Summary of Wind Velocity Ratios under Summer Wind Directions AECOM Asia Co. Ltd. 3 April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary 1 INTRODUCTION 1.1 AECOM Asia Company Ltd. was commissioned by the Planning Department (PlanD) to undertake an air ventilation assessment (AVA) for the Development of Container Terminals (CTs) No.1 to 9 under Agreement No. PLNQ 56/2012 Category B - Term Consultancy for Air Ventilation Assessments by Computational Fluid Dynamics (CFD) in February 2013. 1.2 The AVA study aims to carry out an initial study by conducting a quantitative assessment on the likely air ventilation impact under different building height restrictions (BHR) scenarios for the entire Kwai Tsing container port at CTs No.1 to 9. 1.3 The assessment presents the simulation results of the Baseline Scenario and three different options of development schemes (namely Scenario A, Scenario B and Scenario C) provided by PlanD, findings and proposed potential improvement works/mitigation measures. A further revised Scenario C provided by CT operators has also been assessed qualitatively. 2 WIND AVAILABILITY 2.1 Based on the annual wind rose from the MM5 wind data at Kwai Chung obtained from HKUST, the sum of the frequencies of occurrence of wind from ENE, E, NE, ESE, NNE, SE, SSE and S exceeds 75% of the time in the reference year. These 8 wind directions have been selected as the annual prevailing winds for this AVA assessment. 2.2 Based on the summer wind rose from the MM5 wind data at Kwai Chung obtained from HKUST, a total of 9 wind directions including E, ESE, SE, SSE, S, SSW, SW, WSW and NW which account for over 75% of summer occurrence have been selected as the summer prevailing winds for this AVA simulation. Annual and summer prevailing wind roses are shown in Figure 2.1. Annual Prevailing Wind Rose at 450m Elevation Summer Prevailing Wind Rose at 450m Elevation Source: MM5 wind data at Kwai Chung obtained from HKUST Source: MM5 wind data at Kwai Chung obtained from HKUST Figure 2.1 Annual and Summer Prevailing Wind Rose at 450m Elevation AECOM Asia Co. Ltd. 4 April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary 3 EXISTING SITE CONDITIONS 3.1 The subject site of this AVA initial study is defined by the existing locations of Container Terminals (CTs) No.1 to 9 which span over Kwai Chung, Stonecutters Island and Tsing Yi. 3.2 The Project Area covers 3 Outline Zoning Plans (OZPs): the draft Kwai Chung OZP No.S/KC/26, the approved Stonecutters Island OZP No.S/SC/10 and the approved Tsing Yi OZP No.S/TY/24. It measures approximately 2.5km from east to west and 3.5km from north to south, with a total area of 279ha. A total of 32 potential Focus Areas are identified. They are demarcated based on the homogeneity of land use within each area and road pattern. 3.3 The Project Area is located at Kwai Tsing, occupying the waterfront on both sides of Rambler Channel. The topography for CT1-9 is predominantly flat land. The terrain in the immediate vicinity of the Project Area is rather flat with a hilly terrain (i.e. Lai King area) at about 200m to the east of the Project Area. Other major topographical features include future Kwai Chung Park (+40mPD) situated to the north of the CT No.5, the hill in Tsing Yi (+334mPD) to the west of CT No.9 and the hill in Stonecutters Island (+68 mPD) to the south. The area to the north-east of the Project Area possesses higher topographical feature as Golden Hill (+369 mPD) whereas the area to the south of the Project Area is comprised of low-lying water front area. 3.4 The CTs No.1 to 5 fall within the draft Kwai Chung OZP No.S/KC/26, CTs No.6 to 8 within the approved Stonecutters Island OZP No.S/SC10, and CT No. 9 within the approved Tsing Yi OZP No. S/TY/24. All CTs are zoned “Other Specified Used” (“OU”) annotated “Container Terminals”, except the northern portion of CT No.9 which is zoned “OU” annotated “Container Relaters Uses” and “Cargo handling Area”, on their respective OZPs. 3.5 The demarcation of the Project Area, Assessment Area, Surrounding Area, Computational Area and prevailing wind directions are shown in Figure 3.1. NE ENE E E SW ESE SE SSW Annual Prevailing Winds Summer Prevailing Winds Figure 3.1 Project Area, Assessment Area, Surrounding Area and Prevailing wind directions AECOM Asia Co. Ltd. 5 April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary 3.6 Just outside the Project Area is the Assessment Area delineated in green (Figure 3.1). The Assessment Area is usually defined as an area 1H from the Project Area based on the Housing, Planning and Lands Bureau Technical Circular (TC) No.1/06 (2006) and Environment, Transport and Works Bureau TC No. 1/06 (2006) on Air Ventilation Assessment (the Technical Guide) where H is the maximum height of the proposed development inside the Project Area. For this site, the proposed maximum building height is 250mPD. Because of the extensive lateral dimensions of the Project Area (2.7-3.4km), the common value of 1H is considered insufficient to account for the potential cumulative impacts of the proposed development within the Project Area. For prudence, an area of at least 2H i.e. 500m from the Project Area should be adopted as the Assessment Area, with modification to include the whole of a site (e.g. open space, residential site, etc.) if a site is severed during the delineation process. 3.7 The Surrounding Area is an important area that conditions the approach wind flow into the Project Area. It is normally taken as an area 2H from the Project Area according to the Technical Guide. Having reviewed the surrounding topography, buildings and characteristic lengths of the CTs No.1-9 (2.7-3.4km), a square of 6.2km is considered to be adequate (Figure 3.1). Buildings and topographical features are modelled within the Surrounding and Assessment Areas. AECOM Asia Co. Ltd. 6 April 2015 Category B - Term Consultancy For AVA by CFD Container Terminals No. 1 to 9 Planning Department Executive Summary 4 ASSESSMENT METHODOLOGY AND TESTPOINTS LOCATIONS 4.1 This AVA study is carried out in accordance with the guidelines stipulated in the Housing, Planning and Lands Bureau Technical Circular (TC) No.1/06 (2006) and Environment, Transport and Works Bureau TC No. 1/06 (2006) on Air Ventilation Assessment (Technical Guide) for AVA for Developments in Hong Kong with regards to Computational Fluid Dynamics (CFD) modelling. Reference is also made to the “Recommendations on the use of CFD in Predicting Pedestrian Wind Environment” issued by a working group of the COST action C14. Thus, it is considered that the COST action C14 is a valid and good reference for CFD modelling in AVA study.